Method of making puncture sealing material



June 4, 1946. E. EGER 0 ,6

METHOD OF MAKING PUNCTURE SEALING MATERIAL Filed April 15, 1940composition.

Patented; .Eune 4,1946 I ,lutzs Mn'rnon or" MAKING PUNCTURE SEA-LINGMATERIAL Ernst Eger, Grosse Pointe Park, Mich., asslgnor to UnitedStates Rubber Compmm. New York, N. Y., a corporation of New JerseyApplication April 13, 1940, Serial No. 329,461

3 Claims. 1

This ln vention relates to methods of making fpuncture eaung materialand, in particular, it l'e18t-8$- tQ the manufacture of a sheeting of aresilient- :nature and embodying compression stresses. Moreparticularly, the invention relates to the manufacture of a sheet ofrubber composition embodying compression stresses, which stresses aremaintained by a substantially inextensible material forming a part ofthe composite sheet.

In the useof containers or tanks which operate as storage means forretaining fluids such as gasoline, it i sometimes desirable to protectthe tank in the event it should become punctured by some means such as aprojectile. By providing a compression layer of rubber com positionadjacent to a tank wall, the compres= sion rubber functions to close anyopening which may occur in the wall due to the penetration through thewall of a puncturing object such as a projectile.

In general, my invention comprises essentially the formation of atubular sheet formed in part of a layer of substantially inextensiblematerial. and of a layer of relatively soft rubber composition. form andsin vulcanization the substantially Fig. 3 is a transverse view, insection, of puncture sealing material in its relaxed state;

Fig. 4 i an end 'elevational view illustrating the manner in which unitsof puncture sealing material may be joined together to form largersheets of the material to facilitate its application to larger surfaces;

Fig. 5 is a perspective view; partly in section, illustrating a detailedconstruction of a method of attaching puncture sealing material to thecorner portions of a tank; and,

Fig. 6 is a transverse view, in section, of a portion of a containerillustrating a modified form of my invention. I

With reference to the drawing and. in particular, to Fig. 2, I show amethod of forming a puncture sealing material which comprises theformation or assembly of materials on a tubular mandrel or pole I.Specifically, a mandrel of The sheet is vulcanized in tubularineatensible material i bonded with the rubber 0 When the tubular sheetis straightened out in the form of a slab as, for example. in itsapplication to a straight surface gasoline tank, straightening of thesheet causes the inextensible member to exert compression stresses inthe rubber composition, therefore providlng the puncture'sealingcharacteristics of the sheeting.

Among the objects of my invention are to provide apuncture sealing sheetof material which may be applied to fiat or curved surfaces of a tanlr.to prevent loss of fluid notwithstanding a puncture oi the tank; toprovide a puncture sealing sheeting which in itself forms a unitassembly and which may be applied to various uses where puncture sealingcharacteristics are de-= sired; and to provide a puncture sealingsheeting which may be manufactured eminently and economically. These andother objects and advantages will appear more fully in the followingdetailed description when considered in conncc-= of manufacturing thepuncture sealing material;

this type has a diameter of approximately 3 /2 inches. The size ofithemandrel diameter, as well as the thickness of the rubber composition,

determines the amount of compression stresses which are ultimatelyimparted to the rubber composition of the sealing material. As appearinghereinafter, it will be obvious that the larger the diameter of themandrel, the lesser the resultant amount of compression stresses in thesealing material. The mandrel I may be of any desired length suitablefor convenient manufacturlng purposes.

As an initial step preceding the assembly oneration of the sealingmaterial, the mandrel l is coated or painted with lubricating materialsuch as soapstone for the purpose of removing rubberized materialssubsequently applied thereon.

' Around the outer periphery of the mandrel i is I together, I prefer toemploy an additional layer or ply of fabric 3 which is assembled on topof the first ply 2. The plies 2 and 2 may be of the same strip ofmaterial, the ply it merely being the second convolution of the firstply 2. The fabric plies 2 ands .maybe formed of any textile materialwhich is substantially inextensible such as square woven cotton fabric.Cord fabric may also be used, providingthe cords extend substantially inopposite directions in adjacent plies, in order to provide the properdegree of inextensibility. The plies 2 and 3 are also coatedmaterialsuch as soapstone.

' removed from the mandrel I.

. 3 with a rubber composition so as to form rubberized fabric commonlyused in the tire industry.

As shown in Fig. 2, athin strip of metal 4 extending parallel with themarginal portion of the ply 2- is assembled directly on top of the ply2. The purpose of the strip' as described hereinafter is to preventadhesion between portions of the layers 2 and 3 and to permit theassembly to be cut for its removal from the mandrel I. To preventadhesion between plies 2 and 3 in in the region of the metal strip 4, itis preferable to coat the metal strip 4 or the complementary regions ofthe plies 2 and 3 with .a lubricating After the plies have beenassembled to form the equivalent of two complete convolutions, a layerof rubber composition 5 is wrapped around the assembled plies. The totalthickness of the layer of rubber compositionis in the order of of aninch, and it plished by cutting the assembly longitudinally with a knifealong the linel, as indicated in Fig. 2. The knife ispressed firmlythrough the rubber composition 5 and through the fabric layer 3, whilethe metal strip 4 prevents the marginal portion of the ply 2 frombecoming severed from the. remaining portion of the ply.

In assembling the component parts on the 'mandrel, a suitable markingmay be formed on trated is in substantially circular formation in.

cross section, and in ,this state does not embody compression strains inthe rubber. It is also noted in this view that the fabric ply 2 includesa free marginal portion I extending longitudinal- -ly of the assembly.At the opposite end of the fabric reinforcement a portion'of thereinforcement consists of a single layer only of the fabric, in order toprovide a balanced construction when two or more of the units are Joinedtogether. Because the sealing units are originally formed on a mandrelhaving a relatively small diameter,

This is accom- 1 flattened out against a plane wall surface, the

fabric reinforcement being substantially inextensible causes the rubbercomposition to incur compression stresses. The sealing material may beunited to the wall of the tank by a, cementing operation involving acold cure. The compression stresses in the rubber composition are,therefore, permanently maintained therein. While the sealing material,as above stated, may be ccmented to the wall of the tank, it is to beunderstood that any means for holding the sealing material at or inclose proximity to the tank wall will be sufllcient to'accompiish thepurpose of the sealing material by preventing any substantial leaking orloss of fluid from within the tank. For example, fabric or wire mesh Itmay be applied over the sealing material.

As shown in the assembly in Fig 1, reinforcing retain any substantiallow of the fluid. Further-' more, the sealing material as hereinprovidedis' intended to function as a temporary or emergency means forsafeguarding the contents of the tank. It is also to be understood thatin-the event the contents within the tank are of the nature of gasolineand a leakoccurs,-the result will be a swelling of the rubbercomposition. Such a condition is not detrimental in the present casebecause as the rubber swells it thereby increases the compressionstresses in the rubber and improves the quality of the sealing materialagainst loss of the fluid. In place or a rubber composition, othermaterials may be used which are not affected by the action of gasoline.Such materials ing material are cemented together to form, in

effect, a hermetically sealed container exclusive of the tank.Rubberized fabric strips I! may be employed for the purpose of furtherreinforcing the corner portions of the tank.

While I have shown a reinforcing material in I the form of a rubberizedfabric for the purpose of functioning as an inextensible support for thebody of rubber composition, it is to be understood that othermaterialsbesides fabric may be employed. For example, a light weightsheet metal the resulting circumferential length of the unit isrelatively small. To form large sheets from these units, the overlappinglayer I is cemented to the fabric layer of a preceding similar unit andthe abutting edges of the rubber composition I may also be cemented.Such a combination of units is shown in Fig. 4, in which the sections sojoined may .take the form of relatively large rolls. From a roll of thismaterial a tank may be lined... I v

In Fig. 1 is shown a conventional tank I such as is ordinarily employedas a container for gasoline or like materials. In this example, thesealmay be utilized in bonded relationship with the rubber composition.A sealing material which embodies a metal sheet as an inextensiblesupport for the rubber composition may serve with the rubber compositionas the entire wall of a tank. Such a construction is shown in Fig. 6, in

which the sealing material I I3, upon being lapping portions of themetal l5 may be united to adjacent similar units by a solderingoperation.

For a container of this type, in which the rubber composition It isexposed at the inner surface oi the tank, it is preferable to employ arubber or rubber-like composition which is inert to oil and gasolinesuch as the composition sold under the claim and desire to protect byLetters Patent is:

l. The method of making a flat wall having the inherent characteristicof automatically closing a puncture made therein, which consists informing an elongated tube of substantially inextensible flexible sheetmaterial, vulcanizing a relatively thick layer of soft rubbercomposition to the outside or the first mentioned tube to form a tube ofsoft rubber having an external circumference materially greater than theinternal circumference. slitting the tubes lengthwise and straighteningthe first tube into a fiat sheet to hold the material of the second tubein the iorm oi a flat sheet having opposite faces 01' substantiallyequal width and having internal compressive stresses.

2. The methodof making a flat wall having the inherent characteristicsof automatically closing a puncture made therein which consists informing a plurality of layers of substantially limits tensible,flexible. sheet material into a multipleply tube, applying a relativelythick layer of soft rubber composition to the outside of the firstmentioned tube to form a tube of soft rubber have till) ing an externalcircumference materially greater than the internal circumference,vulcanizing the sheet material and soft rubber to form an integral tubewhile maintaining the layers of inextensible material separatethroughout a strip along the length of the tube. slitting the softrubber and one only of the-plies along the length of the tube andstraightening the inextensible sheet material into a flat sheet having afiat body of rubber under internal compressive stresses and having a liof inextensible flexible material projecting therefrom.

3. The method of making a fiat wall having the inherent characteristicsof automatically closing apuncture made therein which consists in winding a single sheet of inextensible material into a tube having aplurality 01' layers, the opposite edges of the sheet material beingdisposed substantially in the same radial plane of the tube. applying arelatively thick layer of soft rubber composition to the outside oi thetube to form a tube of soft rubber having an external circum- Terencematerially greater than the internal sircumference, vulcanizing the softrubber composition and the inextensible sheet material and vulcanizingthe layers of sheet material together except in a strip adjacent theedges of the sheet, said layers being .kept separate throughout thisstrip, slitting the layer of soft rubber and the outermost layer only ofthe inestensible sheet material, and straightening the resultingstructure to form a fiat wall having a sheet of relatively soft rubberunder internal compre ve stresses and having a projecting lip along oneedae.

ERNST EGER.

